Mayor Gavin Newsom at the press conference announcing energy efficiency program with the Department of the Environment and PG&E, Feb. 6, 2007, at San Francisco, CA. ( Lacy Atkins/ San Francsico Chronicle) 39879

When he went before reporters last Thursday to acknowledge he'd had an affair with his campaign manager's wife, San Francisco Mayor Gavin Newsom didn't want to admit he had a drinking problem.

He was still denying it the next day to his press secretary, Peter Ragone -- a denial that Ragone dutifully repeated to the assembled news cameras.

But later that night, Newsom apparently had a change of heart and started thinking about getting treatment for what he now admits is a problem.

According to half a dozen people close to Newsom, who provided a chronology of events, the change of heart began when the mayor got a call from his longtime family friend and political mentor, John Burton, the former U.S. representative and state senator.

Burton had grappled with a cocaine problem himself as a congressman in the 1980s, so as he puts it, he's "been on the other side of the deal." Burton had been reaching out to Newsom in recent weeks after reading reports in this column of the mayor's drinking.

The message was simple: If Newsom wanted to talk, Burton was available.

This time, Newsom -- with news of his affair with a staffer who also was the wife of his campaign manager having been picked up across the country -- was ready.

The two men met Saturday afternoon at a window table at the restaurant run by the Delancey Street substance-abuse recovery program on San Francisco's waterfront.

Burton said they had a frank discussion but declined to go into detail.

After the meeting, Newsom called Burton's good friend Mimi Silbert, director of the Delancey Street program.

Silbert, a longtime player in local, state and national Democratic politics -- whose program is known for its no-frills, no-holds-barred approach -- agreed to help.

Newsom then called his sister, Hillary Newsom Callan, other family members and friends and asked them to meet him at La Barca, a Mexican restaurant on Lombard Street in the Marina District.

There, in the back room, Newsom said both that he had a problem and that he was going to seek help at Delancey Street.

On Monday, Newsom returned to City Hall, not telling anyone of his decision until he announced it out of the blue at an afternoon meeting of department heads.

The news almost knocked his press secretary out of his chair.

As soon as the meeting broke up, Ragone huddled with Newsom's new chief of staff, Phil Ginsburg, then got on the phone to Eric Jaye, Newsom's chief political adviser.

Their choice was either to have the news leak out, drip by drip, or make a formal announcement.

Ragone and Jaye put together a formal announcement. The mayor looked it over, made some changes and made the call to put it out.

"It was probably the first time he's ever made such a big decision completely on his own, which makes me think he's really serious," said one source familiar with the events of the past week.

Most of those we spoke with said they think the mayor will take to the cure if for no other reason than he can't stand the idea of failure.

But as one person who has been close to Newsom over the past year said, "To tell you the truth, I'm not sure if alcohol is the whole problem here. It might be a crutch, but there are other things that need fixing as well.

"But it is a start."

As friends tell it, Newsom's drinking began escalating into a problem just months after his election, when his then-wife, Kimberly Guilfoyle, split for a TV job in New York -- and the mayor chose to console himself by hanging out, often alone, in restaurants and bars.

Newsom could be seen many nights in the Balboa Cafe in the Marina, where he was an investor -- sometimes on his cell phone, often alone, with a glass of wine close by. White wine was his drink of choice.

If not the Balboa then La Barca on Lombard Street, which offered him more privacy in a back room. And there was nearby Rose's Cafe on Union Street as well as Panne E Vino and other restaurants in the area.

If he had a late meeting, he would just run in and grab some food about 10 or 11 p.m. and head home.

And if he didn't have any plans that evening, he'd be at the bar by early evening.

Sometimes, Newsom would meet up with a woman -- telling his police driver to take the rest of the night off while they slipped out the back door.

Occasionally, he would drop in at Tosca's in North Beach -- the last time being a party a couple of weeks back for departing Chief of Staff Steve Kawa -- and around the corner at a disco called Impala.

It was that regular nightlife -- and procession of parties -- that led to the embarrassing episode a few weeks ago when the mayor showed up tipsy at San Francisco General Hospital late on a Friday night to greet the grieving family and colleagues of a police officer who had just been shot to death.

While some of his friends talked of wanting to sit Newsom down, none did.

As one source close the mayor explained, successful politicians aren't that easy to talk to about their personal shortcomings.

"They have the attitude that, 'I got where I am by being who I am.' "

Extra!

Bayview police videographer Andrew Cohen is back -- and this time his target is Mayor Gavin Newsom and his ongoing troubles.

Cohen, whose mock "Cops Gone Wild" video resulted in 24 officers having their badges and guns pulled in 2005, strikes back with a little ditty called "A Dark Day w/ a Hypocritical Twist."